DISSECTION OF THE ORBIT 



343 



recognised viz., a posterior and an anterior. The posterior 

 ciliary arteries run with the ciliary nerves. They arise as 

 two trunks which spring from the ophthalmic whilst it lies 

 below the optic nerve. These divide into several slender 

 branches, which pierce the sclera around the entrance 

 of the optic nerve. Two members of this group of vessels 

 enter the eyeball on either side of the optic nerve, somewhat 



Medial palpebral 

 Dorsal nasal 

 Frontal 



Infra-trochlear nerve 



Anterior ethnioidal 

 artery and nerve 



Posterior ciliary ^ 

 Posterior ethmoidal 

 Ophthalmic 



Supra-orbital 



Arteria centralis 

 retinae 



Posterior ciliary 



Muscular 



Lacrimal 



Ophthalmic 



'Naso-ciliary nerve 

 Internal carotid 



FIG. 136. Diagram of the Ophthalmic Artery and its Branches. 

 (After Quain and Meyer, modified. ) 



apart from the others. They are termed arterice dliares 

 posteriores longce (Fig. 135). The arterice, dliares anterior es 

 come off, in the anterior part of the orbit, from the lacrimal 

 and muscular branches. They vary in number from six to 

 eight, and run to the anterior part of the eyeball, where they 

 form an arterial circle under the conjunctiva. Finally, they 

 pierce the sclera immediately posterior to the cornea. 



Arteria Supraorbitalis. This accompanies the supra-orbital 

 nerve to the forehead, where it was dissected at a previous 

 stage (p. 157). 



